SQLite

  sqlite3_stmt *pStmt = 0;      /* An SQL statement being run */
  char *zSql;                   /* Text of the SQL statement */
  Index *pPrevIdx = 0;          /* Previous index in the loop */
  int idx = 0;                  /* slot in pIdx->aSample[] for next sample */
  int eType;                    /* Datatype of a sample */
  IndexSample *pSample;         /* A slot in pIdx->aSample[] */

  assert( db->lookaside.sz==0 );
  if( !sqlite3FindTable(db, "sqlite_stat3", zDb) ){
    return SQLITE_OK;
  }

  zSql = sqlite3MPrintf(db, 
      "SELECT idx,count(*) FROM %Q.sqlite_stat3"
      " GROUP BY idx", zDb);

    sqlite3DbFree(db, zSql);
  }


  /* Load the statistics from the sqlite_stat3 table. */
#ifdef SQLITE_ENABLE_STAT3
  if( rc==SQLITE_OK ){
    int lookasideSz = db->lookaside.sz;
    db->lookaside.sz = 0;
    rc = loadStat3(db, sInfo.zDatabase);
    db->lookaside.sz = lookasideSz;
  }
#endif

  if( rc==SQLITE_NOMEM ){
    db->mallocFailed = 1;
  }
  return rc;
}


#endif /* SQLITE_OMIT_ANALYZE */

  ** to the elements of the FROM clause.  But we do not want these changes
  ** to be permanent.  So the computation is done on a copy of the SELECT
  ** statement that defines the view.
  */
  assert( pTable->pSelect );
  pSel = sqlite3SelectDup(db, pTable->pSelect, 0);
  if( pSel ){
    u16 lookasideSz = db->lookaside.sz;
    n = pParse->nTab;
    sqlite3SrcListAssignCursors(pParse, pSel->pSrc);
    pTable->nCol = -1;
    db->lookaside.sz = 0;
#ifndef SQLITE_OMIT_AUTHORIZATION
    xAuth = db->xAuth;
    db->xAuth = 0;
    pSelTab = sqlite3ResultSetOfSelect(pParse, pSel);
    db->xAuth = xAuth;
#else
    pSelTab = sqlite3ResultSetOfSelect(pParse, pSel);
#endif
    db->lookaside.sz = lookasideSz;
    pParse->nTab = n;
    if( pSelTab ){
      assert( pTable->aCol==0 );
      pTable->nCol = pSelTab->nCol;
      pTable->aCol = pSelTab->aCol;
      pSelTab->nCol = 0;
      pSelTab->aCol = 0;

  Trigger *pTrigger;              /* Trigger definition to return */
  int iAction = (pChanges!=0);    /* 1 for UPDATE, 0 for DELETE */

  action = pFKey->aAction[iAction];
  pTrigger = pFKey->apTrigger[iAction];

  if( action!=OE_None && !pTrigger ){
    u16 lookasideSz;              /* Copy of db->lookaside.sz */
    char const *zFrom;            /* Name of child table */
    int nFrom;                    /* Length in bytes of zFrom */
    Index *pIdx = 0;              /* Parent key index for this FK */
    int *aiCol = 0;               /* child table cols -> parent key cols */
    TriggerStep *pStep = 0;        /* First (only) step of trigger program */
    Expr *pWhere = 0;             /* WHERE clause of trigger step */
    ExprList *pList = 0;          /* Changes list if ON UPDATE CASCADE */

          pWhere,
          0, 0, 0, 0, 0, 0
      );
      pWhere = 0;
    }

    /* Disable lookaside memory allocation */
    lookasideSz = db->lookaside.sz;
    db->lookaside.sz = 0;

    pTrigger = (Trigger *)sqlite3DbMallocZero(db, 
        sizeof(Trigger) +         /* struct Trigger */
        sizeof(TriggerStep) +     /* Single step in trigger program */
        nFrom + 1                 /* Space for pStep->target.z */
    );
    if( pTrigger ){

      if( pWhen ){
        pWhen = sqlite3PExpr(pParse, TK_NOT, pWhen, 0, 0);
        pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);
      }
    }

    /* Re-enable the lookaside buffer, if it was disabled earlier. */
    db->lookaside.sz = lookasideSz;

    sqlite3ExprDelete(db, pWhere);
    sqlite3ExprDelete(db, pWhen);
    sqlite3ExprListDelete(db, pList);
    sqlite3SelectDelete(db, pSelect);
    if( db->mallocFailed==1 ){
      fkTriggerDelete(db, pTrigger);

    sqlite3EndBenignMalloc();
    if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
  }else{
    pStart = pBuf;
  }
  db->lookaside.pStart = pStart;
  db->lookaside.pFree = 0;
  db->lookaside.szEnabled = db->lookaside.sz = (u16)sz;
  if( pStart ){
    int i;
    LookasideSlot *p;
    assert( sz > (int)sizeof(LookasideSlot*) );
    p = (LookasideSlot*)pStart;
    for(i=cnt-1; i>=0; i--){
      p->pNext = db->lookaside.pFree;
      db->lookaside.pFree = p;
      p = (LookasideSlot*)&((u8*)p)[sz];
    }
    db->lookaside.pEnd = p;
    db->lookaside.bMalloced = pBuf==0 ?1:0;
    assert( db->lookaside.sz>0 );
  }else{
    db->lookaside.pEnd = 0;
    db->lookaside.bMalloced = 0;
    db->lookaside.sz = 0;
  }
  return SQLITE_OK;
}

/*
** Return the mutex associated with a database connection.
*/

/*
** Attempt to allocate an n byte block from the lookaside buffer of
** connection db. If successful, return a pointer to the new allocation.
** Otherwise, return a NULL pointer.
*/
#ifndef SQLITE_OMIT_LOOKASIDE
static void *lookasideAlloc(sqlite3 *db, int n){
  assert( db->lookaside.sz==0 || db->lookaside.sz==db->lookaside.szEnabled );
  if( n>db->lookaside.sz ){
    /* If db->lookaside.sz is 0, then the lookaside buffer is currently
    ** disabled. In this case do not increment the "size misses" stat.  */
    if( db->lookaside.sz ) db->lookaside.anStat[1]++;
  }else{
    LookasideSlot *pBuf;
    if( (pBuf = db->lookaside.pFree)==0 ){
      db->lookaside.anStat[2]++;
    }else{
      db->lookaside.pFree = pBuf->pNext;
      db->lookaside.nOut++;
      db->lookaside.anStat[0]++;
      if( db->lookaside.nOut>db->lookaside.mxOut ){
        db->lookaside.mxOut = db->lookaside.nOut;
      }
    }
    return (void*)pBuf;

  }
  return 0;
}
#else
# define lookasideAlloc(x,y) 0
#endif

    }else{
      p = memAllocate(sqlite3GlobalConfig.m.xCalloc, n);
      if( !p ) db->mallocFailed = 1;
    }
  }

  sqlite3MemdebugSetType(p, MEMTYPE_DB |
         ((db && db->lookaside.sz) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
  return p;
}

/*
** Allocate memory. If the allocation fails, make the mallocFailed 
** flag in the connection pointer.
**

    if( !p ){
      p = memAllocate(sqlite3GlobalConfig.m.xMalloc, n);
      if( !p ) db->mallocFailed = 1;
    }
  }

  sqlite3MemdebugSetType(p, MEMTYPE_DB |
         ((db && db->lookaside.sz) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
  return p;
}

/*
** Resize the block of memory pointed to by p to n bytes. If the
** resize fails, set the mallocFailed flag in the connection object.
*/
void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){
  void *pNew = 0;
  assert( db!=0 );
  assert( sqlite3_mutex_held(db->mutex) );
  if( db->mallocFailed==0 ){
    if( p==0 ){
      return sqlite3DbMallocRaw(db, n);
    }
    if( isLookaside(db, p) ){
      if( n<=db->lookaside.szEnabled ){
        return p;
      }
      pNew = sqlite3DbMallocRaw(db, n);
      if( pNew ){
        memcpy(pNew, p, db->lookaside.szEnabled);
        sqlite3DbFree(db, p);
      }
    }else{
      assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );
      assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );
      sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
      pNew = sqlite3_realloc(p, n);
      if( !pNew ){
        sqlite3MemdebugSetType(p, MEMTYPE_DB|MEMTYPE_HEAP);
        db->mallocFailed = 1;
      }
      sqlite3MemdebugSetType(pNew, MEMTYPE_DB | 
            (db->lookaside.sz ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
    }
  }
  return pNew;
}

/*
** Attempt to reallocate p.  If the reallocation fails, then free p

///////////////////// The CREATE TABLE statement ////////////////////////////
//
cmd ::= create_table create_table_args.
create_table ::= createkw temp(T) TABLE ifnotexists(E) nm(Y) dbnm(Z). {
   sqlite3StartTable(pParse,&Y,&Z,T,0,0,E);
}
createkw(A) ::= CREATE(X).  {
  pParse->db->lookaside.sz = 0;
  A = X;
}
%type ifnotexists {int}
ifnotexists(A) ::= .              {A = 0;}
ifnotexists(A) ::= IF NOT EXISTS. {A = 1;}
%type temp {int}
%ifndef SQLITE_OMIT_TEMPDB

cmd ::= ALTER TABLE fullname(X) RENAME TO nm(Z). {
  sqlite3AlterRenameTable(pParse,X,&Z);
}
cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt column(Y). {
  sqlite3AlterFinishAddColumn(pParse, &Y);
}
add_column_fullname ::= fullname(X). {
  pParse->db->lookaside.sz = 0;
  sqlite3AlterBeginAddColumn(pParse, X);
}
kwcolumn_opt ::= .
kwcolumn_opt ::= COLUMNKW.
%endif  SQLITE_OMIT_ALTERTABLE

//////////////////////// CREATE VIRTUAL TABLE ... /////////////////////////////

  if( pParse->nErr ) return 0;
  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
  db->flags = savedFlags;
  pTab = sqlite3DbMallocZero(db, sizeof(Table) );
  if( pTab==0 ){
    return 0;
  }
  /* The sqlite3ResultSetOfSelect() should only used in contexts where the
  ** lookaside buffer is disabled. */
  assert( db->lookaside.sz==0 );
  pTab->nRef = 1;
  pTab->zName = 0;
  pTab->nRowEst = 1000000;
  selectColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol);
  selectAddColumnTypeAndCollation(pParse, pTab->nCol, pTab->aCol, pSelect);
  pTab->iPKey = -1;
  if( db->mallocFailed ){

** the lookaside subsystem is stored on a linked list of LookasideSlot
** objects.
**
** Lookaside allocations are only allowed for objects that are associated
** with a particular database connection.  Hence, schema information cannot
** be stored in lookaside because in shared cache mode the schema information
** is shared by multiple database connections.  Therefore, while parsing
** schema information, the Lookaside.sz variable is temporarily set to
** zero so that lookaside allocations are not used to construct the schema 
** objects. Lookaside.szEnabled always contains the allocation size that
** Lookaside.sz is set to when the buffer is enabled.
*/
struct Lookaside {
  u16 sz;                 /* Size of each buffer in bytes */
  u16 szEnabled;          /* Value of 'sz' when buffer is enabled. */
  u8 bMalloced;           /* True if pStart obtained from sqlite3_malloc() */
  int nOut;               /* Number of buffers currently checked out */
  int mxOut;              /* Highwater mark for nOut */
  int anStat[3];          /* 0: hits.  1: size misses.  2: full misses */
  LookasideSlot *pFree;   /* List of available buffers */
  void *pStart;           /* First byte of available memory space */
  void *pEnd;             /* First byte past end of available space */

*/
int sqlite3RunParser(Parse *pParse, const char *zSql, char **pzErrMsg){
  int nErr = 0;                   /* Number of errors encountered */
  int i;                          /* Loop counter */
  void *pEngine;                  /* The LEMON-generated LALR(1) parser */
  int tokenType;                  /* type of the next token */
  int lastTokenParsed = -1;       /* type of the previous token */
  u16 lookasideSz;                /* Saved value of db->lookaside.sz */
  sqlite3 *db = pParse->db;       /* The database connection */
  int mxSqlLen;                   /* Max length of an SQL string */


  mxSqlLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
  if( db->activeVdbeCnt==0 ){
    db->u1.isInterrupted = 0;

    return SQLITE_NOMEM;
  }
  assert( pParse->pNewTable==0 );
  assert( pParse->pNewTrigger==0 );
  assert( pParse->nVar==0 );
  assert( pParse->nzVar==0 );
  assert( pParse->azVar==0 );
  lookasideSz = db->lookaside.sz;
  if( db->lookaside.pStart ){
    db->lookaside.sz = db->lookaside.szEnabled;
  }
  while( !db->mallocFailed && zSql[i]!=0 ){
    assert( i>=0 );
    pParse->sLastToken.z = &zSql[i];
    pParse->sLastToken.n = sqlite3GetToken((unsigned char*)&zSql[i],&tokenType);
    i += pParse->sLastToken.n;
    if( i>mxSqlLen ){
      pParse->rc = SQLITE_TOOBIG;

  }
#ifdef YYTRACKMAXSTACKDEPTH
  sqlite3StatusSet(SQLITE_STATUS_PARSER_STACK,
      sqlite3ParserStackPeak(pEngine)
  );
#endif /* YYDEBUG */
  sqlite3ParserFree(pEngine, sqlite3_free);
  db->lookaside.sz = lookasideSz;
  if( db->mallocFailed ){
    pParse->rc = SQLITE_NOMEM;
  }
  if( pParse->rc!=SQLITE_OK && pParse->rc!=SQLITE_DONE && pParse->zErrMsg==0 ){
    sqlite3SetString(&pParse->zErrMsg, db, "%s", sqlite3ErrStr(pParse->rc));
  }
  assert( pzErrMsg!=0 );